On Thu 12-03-15 13:56:00, Marcos Dione wrote: > On Thu, Mar 12, 2015 at 11:35:13AM -0400, Michal Hocko wrote: > > > > On Wed 11-03-15 19:10:44, Marcos Dione wrote: > > [...] > > > > > $ free > > > > > total used free shared buffers cached > > > > > Mem: 396895176 395956332 938844 0 8972 356409952 > > > > > -/+ buffers/cache: 39537408 357357768 > > > > > Swap: 8385788 8385788 0 > > > > > > > > > > This reports 378GiB of RAM, 377 used; of those 8MiB in buffers, > > > > > 339GiB in cache, leaving only 38Gib for processes (for some reason this > > > > > > > > I am not sure I understand your math here. 339G in the cache should be > > > > reclaimable (be careful about the shmem though). It is the rest which > > > > might be harder to reclaim. > > > > > > These 38GiB I mention is the rest of 378 available minus 339 in > > > cache. To me this difference represents the sum of the resident > > > anonymous memory malloc'ed by all processes. Unless there's some othr > > > kind of pages accounted in 'Used'. > > > > The kernel needs memory as well for its internal data structures > > (stacks, page tables, slab objects, memory used by drivers and what not). > > Are those in or out of the total memory reported by free? I had the > impression the were out. 396895176 accounts only for 378.5GiB of the 384 > available in the machine; I assumed the missing 5.5 was kernel memory. I haven't checked the code of `free' but I would expect this to be part of `used'. > > > Yes, but my question was more on the lines of 'why free or > > > /proc/meminfo do not show it'. Maybe it's just that it's difficult to > > > define (like I said, "sum of resident anonymous..." &c) or nobody really > > > cares about this. Maybe I shouldn't either. > > > > meminfo is exporting this information as AnonPages. > > I think that what I'm trying to do is figure out what each value > represents and where it's incuded, as if to make a graph like this > (fields in /proc/meminfo between []'s; dots are inactive, plus signs > active): > > RAM swap other (mmaps) > |------------------------------|-----------------------------|-------------... > |.| kernel [Slab+KernelStack+PageTables+?] > |.| buffers [Buffers] > | . . . . .. .| swap cached (not necesarily like this, but you get the idea) (I'm assuming that it only includes anon pages, shms and private mmaps) [SwapCached] > |++..| resident annon (malloc'ed) [AnonPages/Active/Inactive(anon)] > |+++....+++........| cache [Cached/Active/Inactive(file)] > |+++...| (resident?) shms [Shmem] > |+++..| resident mmaps > |.....| other fs cache > |..| free [MemFree] > |.............| used swap [SwapTotal-SwapFree] > |...............| swap free [SwapFree] > > Note that there are no details on how the swap is used between anon > pages, shm and others; neither about mmaps; except in /proc/<pid>/smaps. Well, the memory management subsystem is rather complex and it is not really trivial to match all the possible combinations into simple counters. I would be interested in the particular usecase where you want the specific information and it is important outside of debugging purposes. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>